Traditional fluid valves operate by moving solid objects to obstruct the flow path. This typically requires sealing against a valve seat and leads to complicated geometries. While valves can be very reliable on the macroscopic scale, on the Micro Electro-Mechanical Systems (MEMS) scale, a number of issues can arise, including producing a valve seat that will seal with acceptably low leak rates, and dealing with contamination and small actuation forces. Moreover, such valves may have complicated geometries with large dead volumes.